Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 230403

Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
1003 PM MDT Thu Jun 22 2017

Issued at 1002 PM MDT Thu Jun 22 2017

Updated to allow the Red Flag Warnings to drop off for portions
of eastern Utah and western Colorado. Relative humidities have
steadily climbed over the past few hours and the wind gradient has
relaxed with the passage of the weak cold front.

UPDATE Issued at 849 PM MDT Thu Jun 22 2017

Updated to cancel the Heat Advisory for southeast Utah and
southwest Colorado. Diurnal cooling combined with an influx of
cooler air behind the weak cold front moving toward the southern
border has caused temperatures to moderate.


.SHORT TERM...(Tonight through Friday night)
Issued at 202 PM MDT Thu Jun 22 2017

The primary forecast challenge this evening remains handling
convective trends and wind gusts along and north of the I-70
corridor. A weak trough aloft, most readily seen as a diffuse
gradient in 700mb temperatures, remains to the north along the
CO/UT border today. This boundary will gradually sag southward
before heading east overnight and into Friday morning. PoPs were
bumped upward along the Roan and Tavaputs into the Flat Tops this
afternoon, and CAM guidance continues to indicate that current
showers/storms will persist through at least 03z before
dissipating along the Continental Divide. Winds have picked up
across a few areas this afternoon, some in association with dry
thunderstorm outflow boundaries. These stronger winds will also
persist through the early evening and the Fire Weather headlines
remain on track.

Overnight temperatures are expected to be notably cooler than in
past nights throughout much of eastern Utah and western Colorado
as the 700mb thermal gradient passes through. Some cloud cover
will linger as well overnight into Friday morning. Forecast
soundings do indicate that most areas should decouple and winds
will not be an issue overnight.

Friday will turn out mostly sunny and we will shave around 5 to 8
degrees off of our afternoon high temperatures. Wind flow will
generally be northwesterly behind the departing trough, with only
a few afternoon cumulus clouds expected in the higher terrain
along the Continental Divide.

.LONG TERM...(Saturday through Thursday)
Issued at 202 PM MDT Thu Jun 22 2017

The weekend forecast remains on track with dry west to
northwesterly flow in place and temperatures about 5 degrees above
normal as the southwestern ridge strengthens. The ridge axis will
pass sometime Monday evening with a few isolated dry thunderstorms
returning to the forecast by that timeframe. The GFS continues to
indicate the potential for another trough moving into the western
CONUS by Wednesday/Thursday. This system is much drier and flatter
than in yesterday`s model cycles however. Still, an uptick in wind
speeds may affect central and northern Utah/Colorado late on
Tuesday and through the day Wednesday. The ECMWF indicates a much
weaker gradient over the region with zonal flow persisting, so
confidence remains low to medium beyond the Day 6 timeframe.


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1002 PM MDT Thu Jun 22 2017

Winds will begin to die down this evening as skies continue to
clear as a weak cold front moves out of the area. This will allow
VFR conditions to prevail for the next 24 hours. However, smoke
from the Brian Head Fire in southwest Utah will inundate the Four
Corners region bringing haze to KDRO.


Issued at 1002 PM MDT Thu Jun 22 2017

Decreasing winds and temperatures, as well as rising levels of
relative humidity, have relieved the area from critical fire
weather conditions. Therefore, the Red Flag Warning has been
cancelled. For Friday and into the weekend, dry northwest flow
will move into the region. However, winds will be lighter and
critical fire weather thresholds are not expected to be met.




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